JPS6357401B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method of extending the dormancy of plants or plant parts and a safe and reliable method of preventing late frost damage in plants. BACKGROUND OF THE INVENTION Plant development, as is well known, proceeds in various parts that can be clearly separated from each other, for example in the germination of seeds, in the budding of perennials, in the formation of flowers and leaves, or in the formation of fruits and seeds. This developmental process is genetically constant, and therefore the internal
It is influenced by so-called endogenous growth factors. However, this endogenous growth factor can be replaced by external, or exogenous, growth factors, such as light, temperature, air,
Interrelated with water and nutrients. Actively growing plants have little resistance to adverse external growth factors, such as frost, heat or excessively low water supply. In order to preserve this property, plants must keep plant parts essential for the survival of the plant, such as seeds, rhizomes, tubers or buds, in a state of dormancy, so-called dormancy, from external conditions that are fatal to the plant. Protect yourself by migrating. During this dormant period, the plant shows no visible growth. This means that sensitive plant parts that can be damaged by unfavorable external conditions are not formed. The beginning and end of the dormant phase, and thus its duration, are largely regulated by environmental factors, such as light and temperature. Extended dormancy is a decisive advantage for practical plant cultivation, especially for fruit and viticulture. This advantage is particularly important under such atmospheric conditions that frosts still have to be expected after active growth.
Such late frosts, which do not occur regularly and with equal intensity every year, damage already budded fruit trees or vines, which are always accompanied by severe yield losses. In the past, attempts to prevent damage caused by late frosts have not been sufficient (see RI Weaver: Grape Growing).
(See John Wiley & Sons, New York, 1976, pages 47-55). The so-called "frost stimulation method" is a frost damage prevention method in the known state of the art.
(Frostb-eregnung), removal of the cold air layer by blowers or direct heating of the fruit tree primordium. All these methods aimed at protecting already sprouted buds and leaves have limited effectiveness or are not economical due to high energy costs. Therefore, attempts have been made to prevent the damage of late frosts by extending the resistant dormancy period using plant hormones (RI Weaver: Plant Growth Substances in Agriculture). Substances in
Agricultuse - 1972, published by WH Freemann & Co - see pages 166-167]. For example, experiments have been carried out using natural plant hormones such as gibberellin or abscisin or synthetic growth inhibitors such as chlorochlorin chloride, but these experiments have not produced the desired effect. Problems to be Solved by the Invention Therefore, the present invention provides a method for extending the dormancy of plants or plant parts, which does not have the above-mentioned drawbacks of the prior art and allows for a highly effective extension of the dormant period despite simple operation. It is based on the problem of developing said method to Means for Solving the Problem The problem is solved according to the invention by treating the plants or plant parts with an aqueous cyanamide solution 4 weeks before or just before the expected emergence date for the respective year in the area of cultivation of the plants. It is solved by That is, it has surprisingly been found that the dormancy period can be significantly extended by the method according to the present invention. This fact, according to West German Patent Application No. 3150404, shows that the cyanamide solution has exactly the opposite effect.
In other words, this was extremely unexpected since it has the effect of resuming the growth of dormant buds. This can only be explained by saying that the point of processing matters. The following budding periods have been reported for four viticulture sites in the Freiburg region (Staudt: aaO: p. 124, p. 116 and 132).
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[Table] As shown in the table above, the germination period differs depending on the cultivation area and year, and the above expected germination date varies depending on the cultivation area and each year. In the case of the method according to the invention, the plants or plant parts to be treated, e.g. buds, rhizomes, tubers,
Apply cyanamide solution on the bulbs and roots.
The optimal treatment date is just before expected emergence, i.e. approximately 1
The time point of treatment has a decisive influence on dormancy extension. The slower the treatment, ie the shorter the time interval between treatment and expected emergence, the longer the delay in emergence will be. In highly advantageous cases, the extension of dormancy can be up to 14 days. Therefore, using the method according to the invention, not only is it generally possible to prolong the dormancy at will, but also the duration of the prolongation can be adjusted consciously via the treatment time point. The aqueous cyanamide solution advantageously ranges from about 0.05 to about 10
% by weight, preferably about 1-3% by weight. Cyanamide solutions can be applied using customary spray equipment and have the advantage of reliable application with good metering. The amount of cyanamide solution used is preferably measured so that the plant or plant part to be treated is completely wetted. Optionally, wetting agents may also be added, in particular alkylaryl polyglycol ethers, such as "Citowett", which preferably contain from about 0.1 to about 1% by weight, based on the cyanamide solution. used in quantity. The method according to the invention is suitable in principle for the treatment of all plants, especially fruit trees and grapes. Important advantages of the method according to the invention are the conscious regulation of the dormant phase and the simple application, as well as the high economic efficiency since cyanamide is a cheap chemical. These advantages are important prerequisites for a reliable and economical method of preventing or completely avoiding crop failure due to late frosts. Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited to these examples. EXAMPLE 1 The grape variety "Noyling" is known for poor emergence in the southern Baden grape growing areas. Additionally, late frosts occur frequently in the area, which can cause serious damage after budding. According to field experience, budding in the experimental year was expected approximately on May 10th. on April 24th, just short of the expected budding date.
15 days ago, add 2.5 cyanamide solution according to the invention
It was sprayed at a concentration of % by weight. As seen from Table 1, the delay in germination was approximately 10 days.

[Table] Example 2 Aconcagua Tal in South America is a relatively new grape growing region. During the normal budding period, day and night temperatures fluctuate relatively drastically. Daytime temperatures can rise above 20°C, but during the night temperatures can fall into the freezing range. An experiment was designed to extend the dormancy period using the grape variety Thompson Seedless, which is extremely important in the area. A 2.5% strength by weight aqueous solution of the active substance cyanamide was sprayed on several days. Normal emergence, predicted by field experience, should have occurred on August 28th. Therefore, the treatment date was set 15 to 0 days before the expected germination date. In fact, the first manifestations of budding, namely the swelling of the buds and the appearance of early leaf hairs (cotton stage or "Cotton Stage"), were observed already on August 28th. This means that in the case of the latest application date, the active substance cyanamide was sprayed on the very last day of the rest period. Late application extended dormancy by 10 days as seen from Table 2.

[Table] Example 3 Experiment year: 1985 Experiment site: Weinsberg Cultivated species: Vitisvinifera, white Riesling

[Table] Example 4 Experimental year: 1986 Experimental site: Vuheinsberg Cultivated species: Vuyteis Vuinifera, white Riesling variety

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Claims (1)

[Claims] 1. A method for extending dormancy of a plant or a plant part,
A method as described above, characterized in that the plants or plant parts are treated with an aqueous cyanamide solution 4 weeks before or just before the expected date of emergence for the respective year in the cultivation area of the plants. 2. Process according to claim 1, using a cyanamide solution having a concentration of 0.05 to 10% by weight. 3. Process according to claim 1 or 2, using a cyanamide solution having a concentration of 1 to 3% by weight. 4 Claims 1 to 3 in which the treated plant or plant part is completely wetted with the cyanamide solution
The method described in any one of the preceding paragraphs. 5. Process according to any one of claims 1 to 4, characterized in that a cyanamide solution containing a wetting agent in an amount of 0.1 to 1% by weight is used.